Did you know that, on average, a car has about 30,000 individual parts? The actual number will vary depending on the type of car and manufacturer. The engine alone contains the highest number of parts, and if we were to consider the engine as a single unit, then the total number of parts in a car will come down to about 1,800. Some of these components see every day, and we interact with them regularly to keep the car in pristine operational condition.
But hidden in this tangle of bolts, joints, etc., are parts of the car that are barely seen at all nor given a second thought unless there is a fault that draws our attention to them. One such part is the tie rod. I will explain the tie rod’s functions, common faults, and replacement costs in this article. Let’s dive in!
What is a tie rod?
A tie rod is a metal bar of high tensile strength that connects the steering rack to the knuckle. The steering knuckle houses the wheel hub (spindle) and suspension. So basically, the tie rod connects the steering to the wheels and helps you control the car. Whenever you steer your car to the right or left, you are engaging the tie rod. Design-wise, the tie rod has two parts, the inner tie rod and the outer tie rod (also known as the tie rod end).
These two parts are threaded together, making it possible to adjust the length to align the front wheels. Tie rods are found in all steering systems, whether it is a rack and pinion or recirculating ball or mechanical type steering. In either of these steering types, there are two tie rod assemblies. One on the left front wheel and the other on the right front wheel. Each assembly has both inner and outer tie rod ends, making a total of four tie rod ends. But there are exceptions.
Are there tie rods at the rear of the vehicle?
Most cars have tie rods only on the front wheels only. The reason is that the primary purpose of a tie rod is to help the driver steer the car by turning the wheels either left, right or straight. So it makes sense that only the front wheels have tie rods. But there are exceptional cases where a car does not have the regular two-wheel steering system (where only the front wheels can be steered by turning the steering).
Instead, the driver can turn all 4 wheels of the car. This type of steering is known as 4-Wheel Steering (4WS) or All Wheel Steering (AWS). In this case, all four wheels will have tie rods. That is two tie rod assemblies in each front wheel and two in each rear wheel. Remember that each tie rod has an outer and inner tie rod end. So we are looking at about 8 tie rod ends in total (4 outer tie rods and 4 inner tie rods) for cars with the 4WS or AWS.
What does the tie rod do?
When it comes to functions, the tie rod pretty much has one of the most important functions in a car. Without it, there is no way you can drive a car. Each time you want to navigate a bend or turn left or right, you will rotate your steering in the direction you want to go. The motion of the steering wheel is transferred through the pinion gear at the end of the steering shaft to the rack, thereby inducing a horizontal motion.
The pinion and rack interface will convert rotational motion into linear motion, which is transmitted through the tie rod to the wheels. So if you turn the steering to the left, the rack moves horizontally in the opposite direction (towards the right). By doing so, it pushes in on the tie rod on the right wheel of the car, and at the same time, it pulls the tie rod attached to the left wheel of the car. This motion causes the right wheel to turn inwards while the left wheel turns outwards, causing the car to move to the left.
Turning the steering to the right will trigger a similar motion in the opposite direction. This is the operation of the rack and pinion-type steering. The mechanical and recirculating ball-type steering uses a different (and slightly more complex) system to convert the rotational motion of the steering shaft into linear motion, which is then transmitted to the wheels by the tie rods.
What are the symptoms of a damaged tie rod?
Perhaps you’ve seen a car sitting right in the middle of the road or by the curb. The first thing you’d notice is how twisted the tires are. It’s almost as if the entire wheel is unhinged, and yes, it is. Although tie rods last for a very long time and, in many cases, you may never need to replace them, they are however prone to wear and tear. The rate at which the tie rod sustains damage depends on the driving conditions.
Most of the damage is concentrated around the outer tie rod, which connects to the wheel hub. If you frequently ply roads with so many potholes and bumps or have been involved in an accident, then these conditions can cause the tie rods to wear out faster and, in the case of an accident, total failure. But before things get so bad, there are certain symptoms to watch out for;
#1. Uneven tire wear
As the tie rod wears out over time, your car’s wheels will no longer align properly. When this happens, the pressure on the tire will be concentrated on just one side instead of being spread evenly over the tire surface. This will cause the tire to wear unevenly (towards the side, taking on the most pressure) and even faster than it should have if the wheels were properly aligned. If you see wear marks along the sides of your car tires, whereas other areas look untouched, this is a sign that there is a problem with the steering system, and the culprit in most cases is the tie rod.
#2. Poor Alignment
Another sign that something is amiss with the tie rod is that the car keeps pulling you towards one side of the road, and it takes your conscious effort to set it straight. This is because the wheels are misaligned. Bad or worn-out tie rods can easily cause your car wheels to come out of alignment. A slight misalignment can impose a lot of stress on the driver because it requires much more effort to keep the car moving straight.
#3. Noise and rattling sound
The outer tie rod or tie end is enclosed in a rubber that keeps specks of dirt away and preserves the lubrication at the steering knuckle. When this rubber breaks or wears out over time, the metallic parts come into contact with each other. This results in a clonking or rattling sound that becomes very audible when turning the car at low speeds. The absence of rubber protection also gives way to sand and grit that make their way into the joint. So instead of a smooth driving experience, there is a constant grinding sensation. This cacophony all points to a worn-out tie rod.
#4. The steering wheel feels loose and vibrates
Usually, operating the steering should feel very smooth. This makes it quite easy to know when there is a problem. The driver will feel a bit jarred when operating the steering wheel when the problem is a worn-out tie rod. This vibration is most likely because the tie rod is loose or the rubber housing at the joint has worn off.
Either way, you can feel the steering wheel vibrate. Additionally, most drivers experience a “feeling out of control” in the sense that there is a slight delay between when they turn the steering wheel and when the wheels of the car respond. You don’t get that instant feedback you would normally get in a fully functioning steering.
How bad is a broken tie rod?
When you see these signs, chances are that the tie rod is the problem here. Now the solution may be as easy as tightening the tie rods to replace them. Of course, you can choose to ignore these signs, but doing so will cost you more in the long run. First, you’d have to replace your tires sooner than necessary and deal with the challenges of driving with misaligned wheels, and then there’s the possibility of a complete and sudden breakdown when the tie rod gets broken. At this point, it will be impossible for you to drive the car. This is why it is recommended to get the tie rods checked or even replaced once you observe the symptoms mentioned above.
How much does it cost to replace the tie rod?
This will depend on the type of car, if both ends or just one end of the assembly needs to be replaced, the quality of the part, and how difficult it is to get a replacement. All things being equal, replacing the tie rod could cost anywhere between $100 to $400 (labor cost inclusive). But this is just a rough estimate. You’ll have to check with your mechanic to know exactly how much it will cost you.
Are tie rods covered under warranty?
Yes. In many cases, the tie rods are covered under warranty. This could be the standard manufacturer’s warranty or third-party wear and tear warranty. However, you must read the fine print to know how much the warranty covers. For instance, most manufacturers will replace the tie rod at no cost as long as the vehicle is within a specific mileage range. Anything outside that range will not be covered under the warranty. Also, the cause of failure may be factored into the decision.
Conclusion
Tie rods are simple metallic bars that allow the driver to control the car. Without them, driving will be impossible, and tie rods are often overlooked because they have a relatively long lifespan. Until a problem arises. In this article, I’ve covered major issues surrounding the tie rod, and hopefully, this answers your questions.
Iliah is the co-founder of Mechanic Ask, where he writes detailed step-by-step tutorials for repairs and mods. He also posts videos walking through things like engine swaps, suspension lifts, and tuning chips. Iliah uses his blog as an educational resource for car enthusiasts based on the knowledge he’s gained from 15 years as an ASE-certified master technician. His repair manuals provide even novice readers the confidence to take on big projects.
